zookeeper-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Yogesh Patil <patyog...@gmail.com>
Subject Re: Data part in z-node
Date Thu, 13 Nov 2014 06:15:23 GMT
Hello  Jürgen,

Thank you very much. Explanation you provided in quite concise and clear.
Shall explore further ZK capabilities.

Cheers,
Yogesh

On Thu, Nov 13, 2014 at 1:05 AM, "Jürgen Wagner (DVT)" <
juergen.wagner@devoteam.com> wrote:

>  Hello Yogesh,
>   it depends on what you want to do. In any case, a znode is not an
> attribute-value store but simply a container for a single array of bytes.
>
> If you will tend to update a whole set of attributes at the same time and
> retrieve them as a set, you could put that into a format of your choice,
> e.g., assign the znode /Controller1 the value
>
> set /Controller1 ip=10.22.1.39,port=8383,type=spare,user=svc_node_11
>
> or JSON
>
> set /Controller1 '{"ip": "10.22.1.39", "port": 8383, "type":"spare",
> "user": "svc_node_11"}'
>
> or XML
>
> set /Controller1
> '<descriptor><ip>10.22.1.39</ip><port>8383</port><type>spare</type><user>svc_node_11</user></descriptor>'
>
> If you want to update fields separately and maybe also retrieve them
> separately, it is advised to put data into different znodes:
>
> set /Controller1/ip 10.22.1.39
> set /Controller1/port 8383
> set /Controller1/type spare
> set /Controller1/user svc_node_11
>
> If you always retrieve some fields together, you could replace the first
> two in the example by
>
> set /Controller1/address 10.22.1.39:8383
>
> The benefit of having separate znodes is also that you can set watches in
> a more fine-grained fashion, e.g., if you're only interested in changes to
> the ip and port (or address) attributes.
>
> Best regards,
> --Jürgen
>
>
> On 13.11.2014 06:37, Yogesh Patil wrote:
>
> Hi,
> Pardon me if this turns out to be too silly a question.
>
> My understanding of znode and data at that node was: like UNIX file stores
> data spanning multiple lines, znode can also have multiple data values.
> However it seems that was wrong.
>
> I ran following set of commands and I could see that each znode can only
> store one data unit (say some string).
>
> [zk: 192.168.0.1:2181(CONNECTED) 15] set /Controller1 IP=192.168.0.1
> [zk: 192.168.0.1:2181(CONNECTED) 16] get /Controller1
> IP=192.168.0.1
>
> [zk: 192.168.0.1:2181(CONNECTED) 15] set /Controller1 port=6655
> [zk: 192.168.0.1:2181(CONNECTED) 16] get /Controller1
> port=6655    <<<<< See data field 'IP' is lost and overwritten by port
data
>
> does that mean I have to create one znode for every type of data that I
> want to store??
> i.e.
> [zk: 192.168.0.1:2181(CONNECTED) 15] set /Controller1/IP 192.168.0.1
> [zk: 192.168.0.1:2181(CONNECTED) 15] set /Controller1/port 6655
>
> Kindly let me know if I am missing something here.
>
>
>
>
> Thanks,
> Yogesh Patil
>
> Graduate Student
> University of Florida
>
>
>
>
> --
>
> Mit freundlichen Grüßen/Kind regards/Cordialement vôtre/Atentamente/С
> уважением
> *i.A. Jürgen Wagner*
> Head of Competence Center "Intelligence"
> & Senior Cloud Consultant
>
> Devoteam GmbH, Industriestr. 3, 70565 Stuttgart, Germany
> Phone: +49 6151 868-8725, Fax: +49 711 13353-53, Mobile: +49 171 864 1543
> E-Mail: juergen.wagner@devoteam.com, URL: www.devoteam.de
> ------------------------------
> Managing Board: Jürgen Hatzipantelis (CEO)
> Address of Record: 64331 Weiterstadt, Germany; Commercial Register:
> Amtsgericht Darmstadt HRB 6450; Tax Number: DE 172 993 071
>
>
>


-- 
Sincerely,

*Yogesh Patil*

+1 352 870 9326

3800 SW, 34th Street
Apt-B16, Gainesville, 32608
Florida, USA

<http://www.linkedin.com/in/yogeshdpatil/>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message